1. Field of the Invention
In general, the present invention pertains to timing apparatuses which are particularly adapted for use in alternately operating control switches in measured timed sequences. Specifically, this invention is directed to a novel and improved timing apparatus including a switching apparatus for accurately, continuously, and reliably operating electrical devices, such as high and low temperature thermostats for furnaces and the like, in predetermined time sequences notwithstanding shutdowns or other interruptions in electrical power.
2. Description of the Prior Art
Heretofore, it has been relatively well-known in the field of environmental control systems to operate temperature control units for regulating furnaces and other like apparatus for the purpose of providing a variety of operating temperature conditions during certain increments of time. For instance, it is common practice to operate a furnace or heater in a plant, office or home, at one particular temperature level during the day and usually have such furnace turned off during the night. Normally, in these situations, however, during the time such heaters or furnaces start-up and heat the surrounding environment to the desired temperature a significant amount of energy is expended. It has been recognized from the standpoint of energy conservation not to mention environmental comfort that the heaters and furnaces should be consistently and reliably controlled by appropriate temperature control units associated therewith so as to minimize overall energy loss as well as avoid costly start-ups. One approach which has been taken is to operate a furnace during prescribed periods of time during the day and night. However, with imprecise timing control, fuel and/or electrical energy might also otherwise be unnecessarily wasted because, for instance, the desired and relatively economical temperature levels desired during segments of a particular time of the day or night will be unable to be achieved. For example, should a high temperature thermostat be set to operate the furnace at 6 a.m., but, instead, commences operation at 3 a.m., it will be readily evident that the furnace is unnecessarily wasting energy during such time.
One of the earlier attempts to provide a successful day/night temperature controller in this particular field is generally described in U.S. Pat. No. 1,471,314. As disclosed in the above referenced patent, an automatic apparatus includes day and night thermostats for alternate operation and control of a furnace, an adjustable clock, and a switching mechanism for shifting between thermostats at any predetermined time of day or night. Such type of approach, however, suffers from the disadvantages at requiring an overall complicated structural arrangement to achieve the switching. Additionally, the particular switch mechanism which is used to accomplish the switching action between opposed thermostats is relatively complicated in construction and less than entirely satisfactory in use. Aside from the preceding disadvantages, such an apparatus is subject to the shortcomings of being incapable of maintaining the preselected times of operation for the furnace should there be prolonged interruptions of power supplied to the motor mechanism.
Several present day prior art arrangements of the foregoing described category relating to temperature controlling devices are operated by A.C. motors. One such device includes a clock controlled thermostat as more completely described in U.S. Pat. No. 3,825,872. Such clock controlled thermostat uses a common power source for a timepiece and furnace motor. The timepiece provides the timing sequence for switching of the thermostats. The foregoing constructional arrangement, however, presents certain problems since its continual accuracy is also dependent upon freedom from electrical interruptions and other types of power shutdowns. In general though, interruptions and shutdowns of electrical power are relatively frequently widespread. Consequently, there is no assurance that the timepiece will be consistently accurate in precisely actuating the switches at the preselected times. Therefore, this type of noted switching arrangement is unable to successfully perform in the manner intended. Another drawback associated with similar forms of A.C. clock controlled thermostats notwithstanding power interruptions resulting in the power lines is the rather conventional practice to provide furnaces or heaters themselves with safety features that are operable to turn off the power. As a result, the timing motor is similarly turned off. Consequently, the selected timing sequences which the thermostats are intended to follow will be offset. Such offset, as mentioned, may be frequently further compounded by repeated safety shutdowns or other interruptions in power. It will, therefore, be readily evident from the preceding discussion that over relatively prolonged periods of time rather substantial deviations between the desired and actual switching time sequences often develop. In such eventuality, the particular switching systems, of course, are not entirely satisfactory. Moreover, such kind of switching systems define a rather complicated and relatively expensive mechanism to construct and operate within the desired prescribed intervals of time.
A more recent attempt which has been taken to improve over the heretofore generally known prior art is a battery operated thermostat timer. While this particular approach overcomes many of the disadvantages associated with A.C. power in operating a thermostat timer it, too, is also subject to drawbacks. Foremost among these drawbacks is the fact that many batteries do not successfully operate for more than one year. Accordingly, battery replacements become necessary and are expensive over relatively prolonged periods of time.
While a known clock system, as is generally described in U.S. Pat. No. 3,902,311, uses a trickle charger for charging a battery, such system does not, on the other hand, use the trickle charger to maintain the battery as the primary and exclusive source of power for operating the clock.
From the above general description of known types of clock controlled thermostat systems particularly adapted for use in controlling the operation of a furnace in controlled time intervals, it will be appreciated that they suffer from several disadvantages. Primarily such disadvantages are that they fail to continuously, accurately and economically control the switching operations of thermostats by a simplified and highly advantageous timing apparatus in predetermined time intervals, regardless of shutoff in the power supply, and, in a manner which does not require repeated and costly replacement of batteries. Aside from the foregoing described shortcomings, heretofore known mechanisms for accomplishing the foregoing are somewhat complicated in construction and relatively uneconomical in manufacture and are generally unreliable in operation.